PROJECT SUMMARY Background and Mission. The Prevention Research Center in St. Louis (PRC-StL) is comprised of practice, policy, community, and academic partners. Housing nine active projects, the PRC-StL is located in a large and vibrant research environment. Matching contributions from Washington University in St. Louis total $875,000 over the 5-year funding cycle. Our mission is to apply expertise in implementation science and evidence-based policy research to prevent chronic diseases, improve health equity, and promote population health. Proposed Core Research Project. Our research project will develop and disseminate approaches to increase implementation of evidence-based policies (EBPs) to reduce obesity disparities and promote health equity, fo- cusing on the uptake of effective local-level policies. We target two specific types of policy makers at the com- munity level: elected local officials (mayors, city council members) and appointed local officials (heads of local departments). We will work closely with a Community Advisory Board that has a wealth of experience in imple- mentation, local government, policy research, obesity prevention, and dissemination. In Aim 1, we will describe the prevalence and contextual determinants of local EBPs in a sample of 200 communities experiencing obe- sity disparities. In Aim 2, we will test a set of approaches for translation of research about obesity EBPs among local policy makers. Aim 2 involves a randomized trial of 320 local policy makers (160 elected officials, 160 ap- pointed officials) that tests research translation of policy briefs into local policy makers? decisions to support EBP adoption. There are four conditions: usual care, risk framing, narrative, and risk framing + narrative. In Aim 3, we will test the effect of social network-informed tailoring of implementation strategies on a variety of policy-relevant processes and outcomes related to EBPs to address obesity. Network models in 20 communi- ties (10 intervention, 10 control) will highlight differences in network structure (e.g., density, presence of iso- lates) that are likely to influence communication about and uptake of obesity EBPs. Building on data from Aims 1 and 2, we will apply and evaluate the effects of stakeholder-driven implementation strategies (e.g., policy briefs, social media) on policy-relevant outcomes such as communication about and uptake of EBPs. Translation, Dissemination, Innovation, and Impact. By applying our Translation Plan, our team will take a sys- tematic approach when disseminating project findings, recognizing that different audiences require specific communication messages and channels. Our project is innovative and impactful because: (1) understanding the drivers of an effective policy process can lead to sustained use of existing resources; (2) the use of social network analysis, relatively new for implementation science, has high potential to elucidate network predictors of implementation; (3) our study will be among the first to describe the role of narrative communication in shap- ing local-level policy in areas with health disparities; and (4) using mixed methods, our study will help to better define the local policy process, content, and outcomes, which are fundamental to EBPs and poorly understood.